#include<iostream>
#include<math.h>

//https://www.nowcoder.com/practice/e05d1c142b3d4898be7183289a00ce5f?tpId=225&tags=&title=&difficulty=0&judgeStatus=0&rp=0&sourceUrl=https%3A%2F%2Fwww.nowcoder.com%2Fexam%2Foj

using namespace std;

int main() {
    int sum = 0;
    for (int i = 1; i <= 10; i++) {
        sum += pow(10, i) - 1;
    }
    cout << sum << endl;
    return  0;
}



